/Engine/Source/Runtime/RHI/Public/RHIResources.h
Shaders that will be invoked if a ray misses all geometry. If this table is empty, then a built-in default miss shader will be used that sets HitT member of FMinimalPayload to -1. Desired miss shader can be selected by providing MissShaderIndex to TraceRay() function.
void SetMissShaderTable ( const [TArrayView](API\Runtime\Core\Containers\TArrayView)< [FRHIRayTracingShader](API\Runtime\RHI\FRHIRayTracingShader) * > & InMissShaders, uint64 Hash )